1. Field of the Invention
This invention relates to an apparatus for needling a nonwoven web comprising a brushlike pierceable support, which consists of an endless backing, which is trained around reversing pulleys and provided with a covering of bristles.
2. Description of the Prior Art
When it is desired so to needle a nonwoven web that it is provided with a structural surface or a surface pattern, it is usual to vary the depth to which the needles penetrate into the nonwoven web so that fiber loops differing in length are drawn in dependence on the varying depth of penetration and said fiber loops will then determine the surface texture of the nonwoven web. The depth of penetration may be controlled by an adjustment of the midstroke position of the needles relative to the support for the nonwoven web or by a vertical adjustment of the support for the nonwoven web. But the adjustment of the depth of penetration of the needles will substantially increase the structural expenditure, particularly if the needles reciprocate at a high frequency, and the control of the depth of penetration permits a variation of patterns only to a retricted degree.
For a production of structured velour needle felts it is known to provide a brushlike pierceable support rather than performed plates (EP-A-183 952). Said pierceable support comprises an endless backing, which is trained around reversing pulleys and provided with a covering of bristles, which can be pierced by the needles indenpendently of a pattern of holes and is moved in unison with the nonwoven web so that a restraint as may occur adjacent to the holes of perforated plates will be avoided. But said known brushlike pierceable supports are to be used to make a fabric which has an appearance that is as uniform as possible and is free of an orientation as far as possible.